1. Field of the Invention
The present invention relates to an image display apparatus that displays a series of images obtained by imaging a subject in time sequence.
2. Description of the Related Art
Recently, a swallowable capsule endoscope provided with an imaging function and a radio communication function has been proposed in an endoscope field, and a capsule endoscope system for acquiring an image in a subject with the use of the capsule endoscope has been developed. The capsule endoscope moves in a body cavity, for example, inside of internal organs such as stomach, small intestine, etc., due to peristaltic movement, and functions to capture an image inside the subject at an interval of 0.5 second, during the period from when it is swallowed from a mouth of the subject for observation (examination) to when it is naturally discharged.
While the capsule endoscope moves in the subject, the image captured by the capsule endoscope is transmitted sequentially to an external receiving apparatus via radio communication. The receiving apparatus has a radio communication function and a memory function. It sequentially stores the image of the inside of the subject received from the capsule endoscope into a memory. By carrying the receiving apparatus, the subject can freely move during the period from when he/she swallows the capsule endoscope to when it is naturally discharged. After the capsule endoscope is naturally discharged from the subject, a doctor or nurse causes an image display apparatus to read the image accumulated in the memory for displaying the image of the internal organs in the subject by the image display apparatus, whereby the doctor or nurse can perform diagnosis of the subject (for example, see Japanese Patent Application Laid-Open No. 2003-19111).
The image display apparatus described above generally displays each image contained in a series of images of the inside of the subject as a still image, or displays each image consecutively to display a pseudo-moving image of the inside of the subject. There is one of such image display apparatuses having a moving image display function described above in which, in order to perform a display operation of a moving image on a screen, a slider that is a rectangle display area and a knob moving in the slider are displayed on a screen, and the knob is moved by a drag operation with the use of a mouse to carry out a display operation of a moving image (see, for example, Japanese Patent Application Laid-Open No. 11-32304). In the image display apparatus disclosed in Japanese Patent Application Laid-Open No. 11-32304, an origin is provided in the vicinity of the center of the slider on the screen, and when the knob is moved so as to be apart from the origin, the moving image is displayed with a reproduction speed according to the position of the knob. On the other hand, there is an image display apparatus that displays icon formed with plural button sections for operating a moving direction and moving speed of an image, and has a function of moving the image on a screen in a desired direction by selecting any one of button sections of the icon with the movement of the mouse and performing a click operation (see, for example, Japanese Patent Application Laid-Open No. 2003-346172).
However, whenever a desired image group, e.g., a series of images in the subject, is displayed with its play speed and play direction (specifically, forward direction or reverse direction in the time sequence) changed to the desired play speed and play direction, a display operation for moving the mouse should be performed, i.e., a cursor on the screen should be moved to the icon, etc., to perform a click operation or drag operation in the conventional image display apparatus. Therefore, there has been a problem that it is in many cases difficult to perform the display operation of the image while observing a series of images in the subject.